High-pressure circulating pump



Jan. 8 1924.

1,480,040 E.IH. ARNOLD ET AL HIGH PRESSUR CIRCULATING PUMP Filed June 29. 1921 2 sheets-sheet 1 l EM 0970,40@

Jan. 8 1924. 1,480,040

Y E. H. ARNOLD ET Al.

HIGH PRESSURE CIRCULATING PUMP Filed June 29 1921 2 Sheets-Sheet 2 mg. Y

@guyz/46M Patented Jan. 8, 1924.

UNITE@ STATES PATENT oFFlcE.

EDWIN H. ARNOLD, OF COVENTRY, .AND WILLIAM( T. WAKEFORD, OF WARWICK DOWNS,

RHODE ISLAND, ASSIGNORS TO THE NITROGEN CORPORATION, 0F IPROVIDENCIEH RHODE ISLAND, A CORPORATION OF RHODE' ISLAND.

HIGH-PRESSURE GIRCUIJATING PUMP.

Application filed June 29, 1921. Serial No. 481,206.

This invention relates to a high pressure circulating pump especially adapted for use in connection with the handling of gases under high pressure, such, for example, as hydrogen and nitrogen.

In the use of highly diffusive gases under high pressures such as are employed, foi` example, in the synthesis of ammonia, it is j exceedingly diiiicult to place the gases under the pressures at which the synthetic operation may be most eiiiciently carried out by means of the pumps heretofore used, by reason of the fact that such pumps are not adapted to withstand the high pressures to which they are subjected and the slightest leak which may develop tends to lower their efficiency to such a point as to render them practically useless. Moreover, the high pressures employed occasion such a strain upon the parts as to make frequent repairs necessary, which, when the parts to be repaired are inaccessible, causes costly delays.

One object of the invention is to provide an improved pump of this character wherein means is provided for maintaining the piston under a substantial degree of back pressure whereby the amount of force utilized in raising the gases to the required pressure is considerably less than would otherwise be required and the danger of leakage past the piston rings is correspondingly reduced.

Another object of the invention is to provide a construction wherein the number of the parts is greatly reduced to prevent leakage of the gases from the pump cylinder, and the arrangement of the operating parts simplified to permit ready access thereto for the purpose of repair, while at the same time providing a construction capable of withstanding high pressures.

A further object .of the invention is to provide a construction wherein the pump casing may be maintained under high pressure while means is provided for preventing undue axial movement of the crank shaft by reason of the pressures in the casing.

Other objects and advantages of the inventlon relate to details of construction and improved methods of operation as will be. more fully set forth in the detailed description to follow.

Referring to the drawings: i

Fig. l is a longitudinal vertical sectional view of the pump taken along line 11 of Fig. 3.

Fig. 2 is a transverse vertical section taken along line 2 2 of Fig. l.

Fig. 3 is a top plan view of thepump cylinders, and,

Fig. 4 is a detail sectional view of the head portion of one of the pump cylinders showing the valve construction.

In the embodiment of the invention illustrated herewith l designates the shaft casing provided at opposite ends with aligned openings 2 of sufficient size to permit the insertion of the crank shaft 3. The casing l may be formed as an integral casting, the openings 2 in the opposite ends thereof being of sufficient size to permit the insertion of the odset crank portions of the shaft 3 therewithin, or it may be formed from separate sections rigidly bolted together. A pair of end plates t and 5 of similar construction are secured to opposite ends of the crank shaft casing l by means of bolts 6 threaded into the casing and provided with nuts 7 for clamping the end plates firmly against the ends of the casing to prevent leakage therearound. The casing 1 is provided with an annular shoulder 8 adjacent to each of the openings 2 formed therein, and a corre,- spondingly formed shoulder 9 on the cooperating end plate fits thereagainst, suitable packing 10 being interposed between the cooperating shoulders to insure a tight lit therebetween and prevent the escape of gases from the casing.

Since the end plates 4 and 5 are of similar construction only one of these parts will be described in detail, it being understood that the descriptive matter relating thereto applies equally well to the' otherk of said end j plates and its adjunctive devices.

The end plate 4 is provided with a portion ll projecting outwardly therefrom whichA serves to provide an extended bearing for the adjacent end ofthe crank shaft 3. A

shoulderedeborefextends through the projecting portionll of the end plate as well .asfthe main part thereof within which is rotatably mounted the adjacent end of the shaft 3. Withinthe `more constricted portion of the bore fa bearing l2 formed of Babbitt metal or other suitable material is provided for the shaft, said bearing being preferably provided with an enlarged portion 13 projecting within the casing for a `purpose which wili be more fully described hereinafter.

"Suitablefackin-gmaterial 3A- Eis positioned aboutthes aft'fin the enlarged portion of the bore aand is held. in placeyby a suitable gland.l5,-which is inl turn held in position and maybe:suitably/adjusted by a capnut lfthreaded uponlthe exterior surface of the outwardly projecting portion 11 as indicated at 17.

'llhershafft 3 is provided wwith crank-p0rtions 20,^properly located rrelative to the cylinders, to which the connecting rods 22 areaattachedf by. means of `split-bearings or other suitable devices'21l.

"The lcrank shaft is provided with a shouldered portion 27 adjacent each end of thefcasingupon which ispositioned abearingiring 28. v"An opposed bearingfring 29 is mounted upon theenlarged portion 13 ofeach l'bearing 12 previously described, and-arseries -ofl ballsBO are interposed between the: bearing rings 28 and 29- to provide thrust bearings for thetcrank sha-ft andepreventlexcessive movementof the shaftiii-any axial fdirectionunder' the high pressure 'maintained within the; crank casing. Positioned between'each ofthe bearing rings 29"'and 'the inner surface of therespeotive end'plate is a iingf32 for taking'upwear upon thet-hrust bearing and assisting in the properpos'itioning of fthe shaft longitu'dinally offthecasing. The rings 32 lmay if desired, befsplitl to automatically take up the wear'to a certainy extent and prevent undue" play in the bearings or ify the rings 32vare integraltheyI may be readily removed when desired and'replaced by others by merely removing ythe* end` Vplates from the ends ofthe shaft.

ln devices of this character when high pressures are maintained in the crank casing it'hasbeen found that leakage. may develop around=`the shaft in one Aofthe bearings and that'when such leakage once occurs the high pressure in the crank case causes the leak to increase rapidly and tends tofforce the shaft bodily in an axial-direction. The: provision of thrust bearings at the ends of the Ishaft serves to retain the shaft in properposition at all times and thus prevent the danger of a slight leakage being increased by axial movement of the shaft as well as to insure retention-of the shaft in the proper position for actuating the plungers.

.Mounted yupen the yshaft easing 1 lare a pair of integral cylinders each of which is provided with a base portion 37 adapted to fit within an opening 38 formed in the `upper portion of the casing and provided with an annular shoulder 39 for engagement with a similar shoulder 4() carried by the. casing. Suitable packing l1 may be interposed between the meeting faces of the shoulders 39-r and-140.V to prevent leakage from the casing between the meeting surfaces. Each of the cylinders 36 is providedwith an an-nularflange 42 having openingsllifor the reception of bolts la Vwhereby the cylinders may. be firmly clamped to the casing. Nuts i5 are threaded upon the'bolts 4:4 and serve to draw the shoulders 39 and l0 into close engagement -to prevent leakage therebetween.

The particular construction of thepcyl- -inders constitutesy an f important feature vof the invention, as cylinders constructed `in separate. parts. bolted! togethery and ofy such materials as cast iron and cast `steel havey been found to be incapable of withstanding the pressures to which the gases are subjected therein without leakage through: thewjoints or even through `the pores `ofthe material itself. yIn order `to overcome theseA difficulties -wehave formed the cylinders 36 of. forged steel and made them .integral throughout, thus -dispensing with all joints and utilizing a ymaterial capable of withstanding the ypressures employed. For-ged steel has been found-to be sufhciently im-A permeable to gases such as nitrogen and hydrogen as topreventescape of the gases through thematerial to such an eXtentuas-.to interfere with the operation of the pump. Each. cylinder 36 is--provided `Witha main bore 48 within which is reciprocablymounted a piston 50, provid-ed with a plurality ofapis.- to'n ringsvl and suitably connectedf tonone of 'theconnecting rods 22--for reciprocation by: the-crank shaft. Each cylindeiwis also provided witha pair offbores 5.3 Aand 15% formed Iin the `head portion thereof for the reception of. inlet and exhaust valves respectively. Vrlheboreforsthe inlet valve may be somewhat-*f larger in diameter than that for'the outlet valve as the pressure-under which the gas enters the cylinder. is Iless than that at which Ait is discharged. 'The bore 53 -isl preferably formed toprovidean annular shoulder 55v to be 'engagedi by a correspondingly yformed shoulder on the valve block 56, as shown in Eiga of; the drawings. The valve block 56 is provided with an aXial'bore for. the reception ofthe stem"57 vof the inlet valve 58,andthefvalve stem 57 is prov-idedwit-h a vhead59 engaged by a coiled: compression 'spring 60l foinormally holding the valve k58 -in engagement with l'the valve seat.

An annular grooveff62. isY formed in the youter surface oftheva-lve.

block from which eXtend a plurality of passages 63, opening into the cylinder through the valve seat, and which are closed by the valve 58 when the valve is seated. The annular groove 62 communicates with an inlet pipe 64 through which the gases are conveyed to the cylinder from a source of supply which in the present instance may be a compressor wherein the gases have been initially compressed prior to their entry into the cylinder. The upper portion of the bore 53 is internally threaded, as shown in Fig. 4 of the drawings, and a plug 67 is threaded into the upper portion of the bore a sutlicient distance to bear against the upper surface of the valve block 56 and hold the same securely seated in the head portion of the cylinder. The plug 67 is provided with a recess 68 in the inner end thereof for the reception of the valve stem 5 Mounted in the bore 54 is a valve block or sleeve 70 which serves as a seat for the outlet valve 71 slidably mounted therein, and which rests upon a shoulder 7 2 formed in the head portion of the cylinder. An opening 7 3 in the sleeve 70 communicates with the outlet pipe 74 as well as with an annular groove 75 formed in the interior of said sleeve whereby the outlet pipe 74 may be placed in communication with the interior of the cylinder when the inlet valve 71 is raised. The upper portion of theV bore 54 is internally threaded, as shown in Fig. 4 of the drawings, and a plug 78 is threaded therein and bears against the valve block or sleeve 7 0 to hold the same firmly seated against th-e shoulder 72 formed in the head portion of the cylinder. A stem 79 projects downwardly from the plug 78 and is surrounded by a coiled spring 80 which bears against the valve 71 -to normally hold the same in contact with its seat on the sl-eeve 70.

From the above description it will be seen that the pump cylinders being of integral construction, that is, the main body portion and head portion of each cylinder being formed integral, there are no joints or connections through which leakage of the gases may take place, while, by reason of the novel arrangement of the parts they may be as readily and easily constructed as though they were formed in sections. It will be seen that the bore 48 can readily be formed in the cylinder block and then the bores for the inlet and outlet valves formed as well as the openings for the inlet and outlet pipes, all of these openings being readily formed from the outside of Ithe cylinders with the same facility as though the cylinders were sectional. Moreover, the construction of the valves is such as to permit their being readily removed at any time for purposes of replacement or repair by merely removing the corresponding plugs which hold the same in place. The

operative mechanism of each valve is securely held against accidental displacement by means of the plugs threaded into the head portion of the cylinder and bearing against the valve par-ts to hold them firmly in contact with their respective seats.

The upper portion of each cylinder is cored out as indicated at 81 to form spaced annular flanges 82 and 83 to which a cylindrical shell 84 may be secured to provide a water jacket for cooling the cylinder, water being circulated therethrough in any desired manner as by means of pipes 85 and 86.

The crank casing is preferably maintained under a pressure substantially equal to that at which the incoming gases are admitted to the cylinders by means of a pipe 88. connecting the inlet pipe 64 with the interior of the crank casing 1. The source of supply or reservoir from which the gases are drawn together with the cubical contents of the cylinder being relatively large as compared with the piston displacement, the return movement of the piston will have no appreciable effect in compressing the gases in the crank casing, and in the case of two cylinders being employed, as in the embodiment shown herewith, the tendency of one piston to compress the gases in the crank casing on its return stroke will be counterbalanced by th-e advance of the other piston. It is proposed to utilize the structure shown herewith, for example, in acting upon gases already under a pressure of from 800 to 1000 pounds per square inch, and to compress such gases in the pump so that they may be delivered therefrom under pressures of from 1200 to 1500 pounds per square inch. It will be obvious therefore that the advantages to be obtained by admitting such gases, to the crank casing whereby a substantially constant back pressure will be maintained on the pistons serves to greatly reduce the amount of power necessary to be employed in the further compressing of the gases. By means of the present arrangement there is practically no circulation of th-e gases through the crank casing with consequent liability of contamination by contact with oil or other materials therein. While for the purpose of illustration cer-tain specied pressures have been stated as capable of being utilized in the operation of the mechanism for the purpose of compressing gases in the manner described, it is to be understood that the mechanism is not limited to use under the pressures the same or substantially the same as set forth, butthat the pressures mentioned are cited merely as illustrative of one use of the structure.

Having described our invention, what we claim is:

1. A high pressure circulating pump comprising a crank casin provided with openings at opposite en s thereof, end plates secured to saidcasing and serving as closures for said openings, said end plates being provided With bearings for supporting a crank shaft, a crank shaft positioned in said casing and rotatably supported by said bearings, integral cylinders secured .to said casingy and each provided with a main bore communicating with the interior of the casing and bored inlet and outlet valve `passages having their axes substantially paral" lel With the axis of the main bore, and pistons reciprocably mounted in the main bores of said cylinders and operatively connected with said crank shaft.

2. A high pressure circulating pump comprising a crank casing, a crank shaft mounted Within said crank casing, bearings for lies-ane@ rotatably .suppol-tingsaid ,crank shaft, `an integral. cylinder secured. toY said casing `and provided With a main ,bore communicating with the interior .of said casing vandbored inlet andfoutlet .valve passages communicating with saidy .bore, inlet` and Outlet valve", structures .mounted in said valve Vpassagesr a piston reciprocably mounted s in. the main borezzof, said Ycylindei." and operatively connected with said crankshaft, land means for Apreventing Aaxial movement fof said crank. shaft insaid casing.

Iny testimony Hwhereof We have, affixed our signatures.

EDWINH. ARNOLD. WILLIAM T. WAKEFQSRD. 

